Stratification

The funny zebra-like patterns shown in this figure emerge when a mixture of large - rough and small - smooth particles are poured on a heap.

With Yan Grasselli we measured the dependence of the wavelength on filling rate, cell geometrie and particle size. This was published in Granular Matter Vol.1, p.43-47 (1998).

With Hernan Makse we made a model of particles jumping down a heap surface which reproduced the observed segregation patterns including the above strata as seen in the figure left. More can be found in the paper published in Europhys. Lett., Vol. 43, p. 1-6 (1998).